What is the most effective offline promotional technique in assisting an online PPC search campaign?

Of course it depends on the amount of money you are willing to throw into a branding campaign, but which offline promotional channel (print, TV, radio) is most effective in driving consumers online and acquiring new customers? Are there any resources out there that may have covered some of the same ground before?

Promotional Product advertising has shown to be extremely effective, more so than any other promotional channel. People who receive promotional products are receiving a tangible item that stands on its own. In most cases, these products are considered useful items (pens, calendars, drinkware) and are used by the recipient. Research by the Promotional Product Association International (PPAI) shows that 76% of people who recieved a promotional product within the past 12 months could recall the advertisers name. Only 53% could recall an advertiser that they had seen in a newspaper or magazine.